1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to a drive control device for controlling the drive of an image forming motor and a laser scanning unit in an image forming apparatus.
2. Related Art
In general, an image forming apparatus, such as, a printer, a facsimile machine, a photocopier and a multi-functional product, is typically provided with an engine driving unit, a laser scanning unit, and a control unit operable with a control panel. Typically, the engine driving unit is provided with one or more driving motors for driving one or more components, such as a conveying unit, a photosensitive body such as a photoreceptor drum, a developer unit, a fusing unit, a discharging unit and the like, to form an image on a printable medium with a certain process speed. One or more driving motors are connected to each of the units through a power transmitting gear train and are driven by a power switching device. The laser scanning unit is provided with one or more laser sources and a support structure to scan a laser beam to form an electrostatic latent image on the photosensitive body. Such a laser scanning unit is also driven by a power switching device.
Conventional power switching devices can be costly to install, and can drive the cost of such an image forming apparatus unnecessarily. In generally, there are different types of power switching devices used to drive the laser scanning unit (LSU) and the one or more driving motors in the image forming apparatus.
FIG. 1 is a block diagram of a first typical drive control device for use in an image forming apparatus. As shown in FIG. 1, a first power switch 10 and a second power switch 30, which are mechanical switches, are arranged to control the drive of a laser scanning unit (LSU) 20 and one or more driving motors 40. Typically, the first switch 10 receives a voltage of 5 V from a power source, and controls the drive of the laser scanning unit (LSU) 20 by a switching operation to scan a laser beam including data information for forming an electrostatic latent image on a photosensitive body. In addition, the second power switch 30 receives a voltage of 24 V from another power source, and controls the drive of the one or more driving motors 40 by a switching operation to form an image on a printable medium. The first power switch 10 and the second power switch 30 turn off the voltage supplied to the laser scanning unit 20 or the one or more driving motors 40, when a cover of the image forming apparatus is opened or a developer cartridge is detached from the image forming apparatus.
FIG. 2 is a block diagram of a second typical drive control device for use in an image forming apparatus. A third power switch 50, which is a mechanical switch, and a regulator 70 are arranged to control the drive of one or more driving motors 60 and a laser scanning unit 80, respectively. That is, the third power switch 50 receives a voltage of 24 V from a power source, and controls the drive of the one or more driving motors 60 and the laser scanning unit 80 by a switching operation. The third switch 50 blocks the voltage supplied to the laser scanning unit 80 and the one or more driving motors 60, when the cover of the image forming apparatus is opened or the developer cartridge is detached from the image forming apparatus. The regulator 70 is used to lower the voltage from 24 V to 5 V, and supplies the voltage of 5 V to the laser scanning unit 80.
If two mechanical switches are used, as shown in FIG. 1, or a single mechanical switch and a regulator are used as shown in FIG. 2, cost of the device for controlling the laser scanning unit and the one or more driving motors in an image forming apparatus increases.
Moreover, if the regulator is utilized in the second drive control device, as shown in FIG. 2, additional heat is generated from such a regulator and, as a result, an additional device or structure for sinking the heat is required.